Interstitial lung disease

Question 1

What conditions are encompassed within interstitial lung disease?

Answer 1

• Idiopathic interstitial pneumonia
  
  • Usual Interstitial Pneumonia (UIP)
  • Non-specific Interstitial Pneumonia (NSIP)
• Extrinsic Allergic Alveolitis
• Sarcoidosis
• Other conditions

Question 2

Differentiate between usual interstitial pneumonia (UIP) and non-specific interstitial pneumonia (NSIP)

Answer 2

High resolution CT appearance

• Usual interstitial pneumonia:
  
  • Apico-basal gradient
  • Heterogeneous
  • Honeycombing
  • Traction bronchiectasis
• Non-specific interstitial pneumonia:
  
  • No gradient
  • Homogeneous
  • Ground-glass opacity
  • Micronodules

Question 3

State two important aspects of Hx to diagnose ILD

Answer 3

• Occupational Hx
• Environmental Hx

Question 4

How can the causes of interstitial lung disease be categorised?

Answer 4

• With known cause
• Associated with systemic disorders
• Idiopathic

Question 5

Name three interstitial lung diseases with known cause

Answer 5

• Occupational
  
  • Asbestosis; coalworker’s pneumoconiosis; byssinosis (cotton, hemp, flax); silicosis; berylliosis
• Drugs
  
  • ^eg. Nitrofurantoin; bleomycin; amiodarone; sulfasalazine
• Extrinsic Allergic Alveolitis
• Infections
  
  • TB; viral; fungal

Question 6

What is Extrinsic Allergic Alveolitis (EAA)?

Answer 6

Hypersensitivity reaction in sensitised individuals following inhalation of organic allergens ^eg. dust; mould; proteins

Includes:

• Farmer’s lung
• Pigeon-fancier’s lung
• Malt worker’s lung
• Sugar worker’s lung

Question 7

Differentiate acute and chronic extrinsic allergic alveolitis

Answer 7

• Acute: acute inflammatory cells infiltrate alveoli
  
  • Fever, rigors
  • Dry cough, dyspnoea, crackles
• Chronic: granuloma formation and obliterative bronchiolitis
  
  • Increase exertional dyspnoea
  • Weight loss
  • T1RF, cor pulmonale

Question 8

Outline the treatement of extrinsic allergic alveolitis

Answer 8

• Acute: may spontaneously settle within 3/7
  
  • Remove allergens
  • 35-60% Oxygen
  • 40mg Prednisolone
• Chronic:
  
  • Avoid allergens
  • Long term steroids

Question 9

Name three interstitial lung diseases associated with systemic disorders

Answer 9

• Sarcoidosis
• Rheumatoid arthritis
• SLE
• Systemic sclerosis
• Sjogren’s syndrome
• Ulcerative colitis
• Autoimmune thyroid disease

Question 10

What is sarcoidosis?

Answer 10

• Multisystem inflammatory disease of unknown cause
• Non-caseating granulomas
• Associated with HLA-DRB1 and DQB1

Question 11

Give three presenting features of sarcoidosis

Answer 11

Asymptomatic: most commonly an incidental finding

• Dyspnoea
• Dry cough
• Malaise; weight loss
• Hypercalcaemia
• Neurosarcoid ^eg. facial nerve palsy

Question 12

How does acute sarcoidosis present?

Answer 12

Löfgren’s syndrome:

• Bilateral hilar lymphadenopathy
• Polyarthlagia
• Erythema nodosum
• Fever

Question 13

Request three investigations for sarcoidosis

Answer 13

• Pulmonary function tests
• CXR
• U+Es; serum ACE; serum Ca²⁺
  
  • ACE and Ca²⁺ produced by granulomas
• Urinary Ca²⁺
• ECG, 24h tape, echo, cardiac MRI
• CT/MRI head

Question 14

What chest x-ray findings are seen with sarcoidosis?

Answer 14

Siltzbach classification (0-4):

• 0: Normal CXR
• 1: Hilar/mediastinal lymphadenopathy
• 2: Lymphadenopathy + parenchymal infiltration
• 3: Parenchymal infiltration only
• 4: Pulmonary fibrosis: upper zones, fissures, and nodules

Question 15

What are the PFT results for the stages of sarcoidosis?

Answer 15

• Stage 0-3: obstructive
• Stage 4: restrictive

Question 16

Name three causes of bilateral hilar lymphadenopathy

Answer 16

• Sarcoidosis
• Infection: ^eg. TB, mycoplasma
• Malignancy
• Organic dust disease: EAA; occupational asthma
• Langerhans cell histiocytosis

Question 17

Outline the treatment of sarcoidosis

Answer 17

60% will self-resolve in 2 yrs

• Acute: bedrest and high-dose prednisolone
• IV methylprednisolone or immunosuppressants, if any of:
  
  • Symptomatic with CXR stage 2 or 3
  • Hypercalcaemia
  • Heart or neuro involvement

Question 18

Outline the diagnostic criteria for idiopathic pulmonary fibrosis

Answer 18

All of the following:

• Exclusion of other known causes of ILD
• Presence of a definite UIP pattern on HRCT prior to biopsy
• Specific combination of HRCT and lung biopsy pattern
• Pulmonary function tests: restrictive pattern + impaired TLCO
• Bx must not show any features to support an alternative Dx.

Question 19

How does idiopathic pulmonary fibrosis present?

Answer 19

Typically aged over 45

• Progressive/persistent exertional dyspnoea
• Persistent dry paroxysmal cough
• Bibasal fine end-inspiratory crepitations
• Clubbing
• Abnormal CXR/CT
• Reduced TLCO and restrictive pattern on spirometry

Question 20

What is the hallmark of IPF?

Answer 20

Absence of inflammation

Question 21

Outline the management of idiopathic pulmonary fibrosis

Answer 21

Aim to slow progression of pulmonary fibrosis

Life expectancy is 3-4y

• Pulmonary rehabilitation
• Smoking cessation
• End of life care; DNACPR; ReSPECT form
• Supportive care
  
  • Supplementary oxygen
  • Consider benzodiazepines/opioids for breathlessness
• Consider anti-fibrotics ^eg. pirfenidone; nintedanib
• Lung transplant